Secondary batteries which are highly applicable to various products and exhibit superior electrical properties such as high energy density, etc. are commonly used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electrical power sources. The secondary battery is drawing attentions as a new energy source for enhancing environment friendliness and energy efficiency in that the use of fossil fuels can be reduced greatly and no byproduct is generated during energy consumption.
Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.5V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity.
Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell first, and then configure a battery pack by using at least one battery module and adding other components.
In the case of the conventional battery module, the technology for efficiently cooling the heat generated at the battery cells is becoming more and more important as the demanded battery capacity is increasing.
For the efficient cooling, in the conventional battery module, a thermally conductive adhesive is applied to the inside of a module case to stably fix a battery cell assembly including at least one battery cell in the module case and to improve thermal conductivity.
However, in the conventional battery module, when an injection hole for injecting the thermally conductive adhesive into the module case is formed, the battery cell assembly in the module case may be damaged due to burr or the like, or an injection nozzle for injecting the thermally conductive adhesive may not be accurately inserted into the injection hole, or the thermally conductive adhesive may leak out of the module case.